Question

spring 注入失败 一直显示java.lang.NullPointerException

<bean id="userDao" class="com.dao.UserDao">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>

<bean id="userService" class="com.service.UserService">
<property name="userDao" ref="userDao"></property>
</bean>

<bean id="request" class="com.action.request">
<property name="userService" ref="userService"></property>
</bean>

action：
package com.action;
import java.util.List;

public class request extends ActionSupport{
private static final long serialVersionUID=1L;
private UserService userService;
private Member user;
public void setUserService(UserService userService)
{
this.userService=userService;
}
public UserService getUserService()
{
return userService;
}
public Member getUser()
{
return user;
}
public void setUser(Member user)
{
this.user=user;
}

public String execute() throws Exception {
try{
Member u=new Member();
u.setUsername(user.getUsername());
u.setPassword(user.getPassword());
u.setEmail(user.getEmail());
userService.saveUser(u);
}
catch(Exception e)
{
e.printStackTrace();
}
return SUCCESS;
}
}
我调过了就是execute里的userService是空的求大神指点！！！

Answer 1

userService
没有初始化，肯定为空
public void setUserService(UserService userService) { this.userService=userService; }
这句话在外边调用过不？没有吧

追问

这不是调用的，是用来给spring框架来注入的stter方法

追答

但是你在外边没注入，那这个变量肯定是空的。